1. Technical Field
This disclosure relates to semiconductor devices, and more particularly, to a testing circuit and a method of detecting defective tips of a probe card and defective wire bonding.
2. Description of the Related Art
Generally, semiconductor devices are completed through semiconductor manufacturing processes such as manufacturing a semiconductor wafer, forming semiconductor chips on the semiconductor wafer, electrical die sorting (EDS) testing to check for failure of the semiconductor chips, packaging good semiconductor chips, and performing final testing of the packaged semiconductor chips, etc. The EDS testing is an operation to determine whether semiconductor chips formed on the semiconductor wafer are defective or not by applying electrical signals to semiconductor chips on a wafer. A tester and a probe card can be used for the EDS testing.
FIG. 1 is a diagram illustrating a method of testing a semiconductor device by using a conventional probe card 20. The conventional probe card 20 includes probe tips TIP11 through TIP1n. A semiconductor device 10 includes pads PAD11 through PAD1n (n being a natural number). The pads PAD11 through PAD1n are electrically connected to internal circuits CIR11 through CIR1n of the semiconductor device 10, respectively. When the EDS testing is performed using the conventional probe card 20, the pads PAD11 through PAD1n are brought in contact with the probe tips TIP11 through TIP1n of the conventional probe card 20, respectively. Testing signals are applied by the tester 30 via the conventional probe card 20 to the pads PAD11 through PAD1n of the semiconductor wafer 10. Electrical characteristic signals are returned via the conventional probe card 20 to the tester 30 in order for the tester 30 to determine whether the semiconductor chips are defective.
During the EDS testing, if there is a contact failure between the pads PAD11 through PAD1n of the semiconductor device 10 and the tips TIP11 through TIP1n of the conventional probe card 20, any defects of the semiconductor device 10 cannot be detected accurately. Such contact failure can occurs when one or more of the tips TIP11 through TIP1n are defective or when foreign substances are interposed between the pads PAD11 through PAD1n and the tips TIP11 through TIP1n, respectively. If there is a contact failure, causes of the contact failure must be eliminated so that the conventional probe card 20 can normally perform the EDS testing.
However, when parallel testing is performed to improve manufacturing yield, it is very difficult to detect the defective tips of the tips TIP11 through TIP1n, because many tips TIP11 through TIP1n are connected to the tester 30 in parallel as shown in FIG. 1. If the defective tips of the tips TIP11 through TIP1n cannot be detected, testing cannot be performed properly, because the conventional probe card 20 cannot be readily repaired or replaced.